With leaders Yorkshire not playing in the latest round of fixtures, the second-placed side showed determination to take advantage as they reduced Somerset to 122 for five at lunch on day one at Taunton.
Openers Nick Compton - overlooked by England this week - and Marcus Trescothick both failed to score, while James Anyon and Steve Magoffin took two wickets apiece. James Hildreth did hit 66 as Somerset recovered from 33 for three but he fell to Chris Jordan.
Third-placed Durham were 97 for two against bottom side Derbyshire at the Emirates Durham ICG.
Keaton Jennings was unbeaten on 46 and Will Smith was 24 not out, with Mark Stoneman and Scott Borthwick the men dismissed, both by Mark Footitt.
Ian Westwood led the way with a half-century as champions Warwickshire started superbly against Middlesex at Uxbridge.
Westwood was 60no with Varun Chopra 35no as Warwickshire reached 103 without loss at the interval.
Surrey lost a wicket just before lunch to slip to 93 for three against Nottinghamshire at the Kia Oval.
- Sports & Recreation
- Marcus Trescothick
- Steve Magoffin
- Nick Compton
- James Anyon
- James Hildreth